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61.
Bovine seminal ribonuclease (BS-RNase), a dimeric homologue of RNase A, cleaves both single- and double-stranded RNA and inhibits the growth of tumor cells. Its catalytic activity against double-stranded RNA, either homopolymeric ([3H]polyA/polyU) or mixed sequence, is enhanced by bovine or human recombinant interferon-γ (IFN-γ). Activation is seen with as little as 4–10 interferon units per assay. Enhancing the degradation of double-stranded RNA, an intermediate in the growth cycle of many viruses, could contribute to IFN-γ's ability to control cell growth and induce an antiviral state. 相似文献
62.
63.
M. Stöhr K. -J. Hutter Monika Frank G. Futterman Kl. Goerttler 《Histochemistry and cell biology》1980,67(2):179-190
Summary Chromosomes from rat kangaroo (PTK) and chinese hamster (CHV 79) cells have been prepared for quantitative flow-cytometric analysis. The preparation time was optimized down to 30 (PTK) and 40 min (CHV 79). DAPI was used as a AT-sensitive fluorescent dye to stain for monoparameter DNA measurements. Simultaneous two-parameter DNA-protein analysis was carried out with DAPI and SR 101 (as a general protein fluorochrome) in combination. The karyotype of the PTK cells with 13 (14) chromosomes was separated into 10 DNA peaks. The X-chromosome bearing the nucleolus organizer region generates a distinct peak. The karyotype of the CHV 79 cells with 22 chromosomes was separated into 15 peaks. The DNA profile obtained indicates a geometric grading of the chromosomal amount of AT components in the karyotype of this particular cell line. The simultaneous DNA-protein analysis performed show enough sensitivity of the instrument utilizing high power UV excitation illumination to discriminate the two color emission consisting of blue (DAPI) and red (SR 101) fluorescence. Color overlapping could be completely avoided. Additionally, the quality (number, location, and resolution of peaks) of the DNA distribution was not influenced by the simultaneous application of a second fluorescent stain. Fluorescence activated electronic sorting applied on chromosomal fluorescence distributions providing purified fractions of chromosomes for subsequent biochemical and biological determinations is discussed. 相似文献
64.
Retention of human skin fibroblast fatty acid modifications during maintenance culture 总被引:1,自引:0,他引:1
Arthur A. Spector Gerene M. Denning Lynn L. Stoll 《In vitro cellular & developmental biology. Plant》1980,16(11):932-940
Summary The fatty acid composition of cultured human skin fibroblasts was modified by adding either oleic or linoleic acid to the
growth medium. After the cultures became confluent, they were washed and transferred to different maintenance media in order
to determine the stability of the various fatty acyl modifications. Some changes in fatty acid composition occurred under
all conditions. When the maintenance medium was supplemented with fatty acid, the cellular neutral lipid and phospholipid
fatty acyl composition were altered markedly within 16 to 24 hr. If no supplemental fatty acid was available during the maintenance
period, however, the modified fatty acyl compositions were sufficiently retained so that appreciable differences between the
cells enriched with oleate and linoleate persisted for at least 48 to 72 hr. This considerable degree of stability occurred
when either 10% delipidized fetal bovine serum or 10% fetal bovine serum containing its inherent lipids were present in the
maintenance medium. Although the triglyceride content of the fatty acid-modified cells was quite labile, neither the cholesterol
nor phospholipid content changed appreciably during culture in any of the maintenance media. Since the fatty acid compositional
differences persisted during several days of maintenance under certain conditions, these modified cultures appear to be a
useful experimental system for assessing the effect of lipid structure on fairly long-term cellular functions.
This work was supported by Arteriosclerosis Specialized Center of Research Grant HL14230 from the National Heart, Lung and
Blood Institute, National Institutes of Health. 相似文献
65.
Effect of dietary phosphate intake on phosphate transport by isolated rat renal brush-border vesicles
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Renal brush-border membrane vesicles isolated from rats kept for 6-8 weeks on a low-phosphate diet (0.15% of dry matter) showed a markedly faster Na(+)-dependent phosphate uptake than did membrane vesicles isolated from animals kept on a high-phosphate diet (2% of dry matter). Phosphate-uptake rate by brush-border membrane vesicles isolated from animals on a low-phosphate diet remained significantly increased after acute parathyroidectomy. Dietary adaptation was also observed in animals that had been parathyroidectomized before exposure to the different diets. In animals on the low-phosphate diet parathyrin administration inhibited phosphate uptake by brush-border vesicles only if the animals were repleted with P(i) (5ml of 20mm-NaH(2)PO(4)) 1h before being killed. After acute phosphate loading and parathyrin administration the difference in the transport rate between the two dietary groups remained statistically significant. The results suggest that the adaptation of proximal-tubule phosphate transport to dietary intake of phosphate is reflected in the Na(+)/phosphate co-transport system located in the luminal membrane of the proximal-tubule cell. Since the dietary effects on phosphate transport by brush-border membranes are only partially reversed by acute changes in parathyrin concentration and are also observed in chronically parathyroidectomized animals, the adaptation of the Na(+)/phosphate co-transport system to dietary phosphate intake seems to involve an additional mechanism independent of parathyrin. 相似文献
66.
Human diploid fibroblasts cultured in Dulbecco's Modified Eagle's medium (DME) were exposed to different concentrations of 15 antibiotics to determine the limiting toxic concentration. The number of cells surviving after antibiotic treatment was given as the index of toxicity. No visible chromosomal damage could be detected when half the maximal toxic concentration was applied. The maximum limiting concentration was found to be the same for both the preconfluent and postconfluent phases. 相似文献
67.
In a woman aged 32, who came for consultation regarding her sterility, a case of Poland's syndrome was diagnosed in view of a brachysyndactylia and a homolateral agenesia of the large pectoral. The possible connexion between her sterility and this syndrome is discussed. 相似文献
68.
69.
R Stoll R Maraud N Faucounau 《Comptes rendus des séances de la Société de biologie et de ses filiales》1975,169(6):1466-1469
In the normal ageing rat is observed a progressive hyperplasia of the C cells. In the rat treated by an antithyroideal drug, the hyperplasia is much more important than in normal. It already appears during the treatment and grows up after its stop. This observation means that the C cells hyperplasia, which reaches later to gamma tumors production, is not due to the TSH oversecreted under the antithyroideal drug influence. 相似文献
70.
R Maraud M Audine R Stoll 《Comptes rendus des séances de la Société de biologie et de ses filiales》1975,169(4):923-927
When a chick embryo, deprived of its hypothalamo-pituitary complex by partial decapitation, is bearing a grafted hypophysis, this gland is unable to induce a normal development of the thyroid. The volume of this gland is reduced and, consequently, the fixation of iodine is decreased from the age of 16 days. Some authors think that there are no hypothalamo-pituitary correlations in the chick embryo. On the contrary, these observations lead to admit their appearance towards the end of the incubation. 相似文献